I. Field of the Invention
The present invention relates to a tire inflation system for a vehicle which enables the tires to be inflated or deflated to operate the vehicle at selected tire deflection levels.
II. Description of the Prior Art
For multi-terrain vehicles, the overall operational efficiency of the vehicle varies as a function of the tire deflection. For example, a relatively high tire pressure inflation, and thus a low tire pressure deflection, is desired for highway travel to minimize tire wear while maximizing fuel mileage. Conversely, a lower tire pressure, and thus a higher tire deflection, is desired for cross country terrain. Such low tire pressures permit more tire deflection and produce a larger tire footprint for increased traction. Tire wear and fuel consumption are not significantly adversely affected by the increased tire deflection when travelling cross country since lower vehicle speeds are normally encountered than with highway travel.
Likewise, even lower tire inflation pressure, and thus higher tire deflection, is desired when the vehicle is travelling through soft earth or sand. Such lower tire pressures create even greater tire deflection thus increasing the tire footprint and traction. Since only very low speeds are encountered when travelling through sand or soft earth, even very low tire pressures do not significantly adversely affect the tire wear or fuel consumption for the vehicle. An even lower tire pressure inflation, and thus maximum tire deflection, is desirable for an emergency situation, such as when the vehicle is stuck, since maximum tire traction is of the utmost importance.
Previously, the tires on a multi-terrain vehicle have been inflated to a compromise pressure so that the vehicle can accommodate different types of terrain without adjustment of the tire pressure. By using a compromise tire inflation pressure, however, the vehicle obtains less than optimum performance for traction, tire wear and fuel consumption.
Furthermore, it is not possible to accurately control the amount of tire deflection by merely changing the tire pressure since the amount of tire deflection is directly proportional to the vehicle load. For example, the amount of tire deflection for a fully loaded vehicle is much greater than the tire deflection for an empty vehicle even though the tire inflation pressures are identical. Furthermore, the amount of tire deflection usually varies between the front and rear tires, even when inflated to the same pressure.